// @(#)FiniteVSFIFOQueue.java   9/2002
// Copyright (c) 1998-2002, Distributed Real-time Computing Lab (DRCL) 
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package drcl.util.queue;

import java.util.*;
//import drcl.RecycleCan;

/**
 * Variable-size version of {@link FIFOQueue}.
 */
public class FiniteVSFIFOQueue extends VSFIFOQueue implements FiniteVSQueue
{
  //public static RecycleCan elementCan =new RecycleCan(_Element.class, 5, 5);
  int capacity = Integer.MAX_VALUE;

  public FiniteVSFIFOQueue()
  {}
                          
  public FiniteVSFIFOQueue(int capacity_)
  { capacity = capacity_; }
                          
  public void enqueue(double key_, Object element_, int size_)
  {
    if (isFull(size_)) return;
    super.enqueue(key_, element_, size_);
  }
  
  public boolean enqueueAfter(Object previousElement_, Object element_, 
          int size_)
  {
    if (isFull(size_)) return false;
    return enqueueAfter(previousElement_, element_, size_);
  }
  
  public boolean enqueueAt(int pos_, double key_, Object element_, int size_)
  {
    if (isFull(size_)) return false;
    return enqueueAt(pos_, key_, element_, size_);
  }
  
  
  public void merge(Queue that_)
  {
    double[] keys_ = (double[]) that_.keys();
    Element[] elements_ = that_._retrieveAll();
    
    if (keys_.length != elements_.length) return; // XXX: throw exception?
    if (keys_.length == 0) return;
    
    if (tail == null) tail = head;
    for (int i=0; i<keys_.length; i++)  {
      int size_ = elements_[i].getSize();
      if (isFull(size_)) return;
      _Element new_ = _Element.create(keys_[i], elements_[i].getObject(),
              size_);
    
      tail.next = new_;
      tail = new_;
      size += size_; length ++;
    }
  }
  
  
  public void enqueue(Object element_, int size_)
  {
    if (isFull(size_)) return;
    super.enqueue(element_, size_);
  }
  
  public String oneline()
  {
    StringBuffer sb_ = new StringBuffer(super.toString() + "," + getSize()
            + "/" + capacity + "," + getLength());
    
    for (_Element e_ = head.next; e_ != null; e_ = e_.next)
      sb_.append("-----" + e_.key + ":" + e_.obj);
    
    return sb_.toString();
  }

  public int getCapacity()
  { return capacity; }

  public void setCapacity(int cap_)
  { capacity = cap_; }

  public boolean isFull()
  { return getSize() == capacity; }

  public boolean isFull(int size_)
  { return getSize() + size_ > capacity; }
}
